American families seem to increasingly prefer cats, with their independent natures and reduced need for care, as compared to dogs. Domesticated animals such as cats are provided with litter boxes, where they dispose of their excretions. The performance of the litter product in the litter box can vary greatly, depending upon the precise nature of the product. Key attributes of a non-clumping litter product, regarded as being highly important by cat owners are: odor control, the degree of freedom from dust, and litter care convenience (i.e., supply and removal).
Two major classes of malodors may develop in a litter box: 1) nitrogen-based malodors, involving, for instance, ammonia from decomposed urine and amines from decomposed fecal matter, and 2) sulfur-based malodors, such as mercaptans, from secondary decomposition. Ideally, cat litters should absorb and/or eliminate the formation of both. Malodors due to volatile ammonia are very pH dependent. Ammonia exists in two molecular forms: 1) volatile ammonia (NH3) and 2) non-volatile ammonium ions NH4+. The equilibrium point between the two forms is at approximately pH 9. The lower the pH from that point, the less the volatile ammonia present. At pH 6.5 and below, ammonia concentration is 0% while non-volatile ammonium ion concentration is 100%.
Originally cat litter products, introduced in 1949, were made of non-swelling clay. Those relatively unsophisticated products are known today as “non-clumping” or “traditional” litters. These clay-based litters are very dusty, and the clay substrates from which they are made has limited absorption capabilities and limited natural malodor suppression capabilities. More recently, in 1989, clumping-type cat litters were introduced. Clumping litters made of bentonite clay are less dusty than traditional ones. Also, the bentonite clay litters are more absorptive and have improved natural odor control qualities.
Operationally, the two types of litters are significantly different. While in both types the method of solid waste removal is essentially the same, they differ with respect to liquid waste removal. Traditional litters simply absorb the urine and hold it. Clumping litters trap the liquid excreta in isolated scoopable clumps, enabling the removal of the urine-laden litter clumps, leaving the remaining litter relatively fresh and free of both liquid and solid excreta. Clumping litters thus provide greater odor control, but this comes at a price of reduced convenience, because a daily scooping routine is mandated, a routine that many non-clumping users find to be an unacceptable burden.
Attempts have been made to improve non-clumping performance by using organic substrates, either natural or artificial. Although organic substrates provide better absorption, and better dust control, they thus far have failed to deliver on the single most important attribute: odor control. Odor control is manifested in two parameters: 1) level of odor suppression and 2) the duration of such suppression. Also, the substrate of organic litters is far less cohesive that is the substrate of clay litters. Organic litters tend to fall apart after a few days in a wet environment in the litter box, turning at that point into a sawdust-like product.
The recent introduction of “Crystal” or “Pearl” type litters, made from silica gel, is one attempt by major animal litter marketers to capitalize on consumer desire for better non-clumping litter. Silica gel litters deliver improved and longer lasting odor control when compared to traditional litters, yet suffer from a very high retail price (being among the most expensive litters ever!) and significant levels of “cat rejection” (that is, cats tend not to like silica gel litters). Another drawback of these litters relates to their aesthetic look after they have absorbed a cat's waste. Silica gel is clear, creating a “see through” effect, unlike other litters that hide the waste. Also, hard and “pointy” silica granules that track out of the litter box can be very painful when stepped on by bare feet.
A non-clumping litter has a tough task to contend with in terms of malodor production dynamics. With “high maintenance” clumping litters, in which solid and liquid waste clumps are removed almost daily, leaving a fresh litter in the box, the groomed litter often lasts 2-3 weeks before full replacement is called for. Replacement eventually becomes necessary due to malodors developing from ongoing build-up of small contaminants originating from broken urine clumps and solid waste remnants “missed” in the clump removal process. In non-clumping litters, however, all urine stays in for the duration of usage, and solid waste stays longer in the tray before being scooped out. In fact, some consumers do not “groom” the litter box at all, they just let it stay untouched until malodors develop and then replace the entire litter tray content.
In non-clumping litters, urine “floods” large portions of the litter that is deployed in the litter tray. Considering that cats normally urinate 3-4 times a day, 20 ml on average each time, it is clear that substantial amounts of urine accumulate. Bacterial load, originating e.g. from the fecal mass, doubles every 20 minutes through natural division, so that large amounts of urine are being decomposed, and usually after 24-36 hours ammonia production is noticeable. After 4-7 days ammonia levels become intolerable. By the time that stage is reached, complexes with fecal-related malodors, also developing as result of bacterial decomposition, mandate entire litter tray content change.
In light of the drawbacks of prior art non-clumping litters, there is a need for a non-clumping litter product that will amalgamate the best properties of all litters: 1) deliver “clumping-litter quality” odor control, 2) provide alternative litter's high absorption, freedom from dust, and “natural” profile, as well as light volume weight, and 3) deliver significantly longer “tray-life” with minimal grooming requirements, as is available with traditional non-clumping litters. To be successful, all of this must be provided in a litter that has high cat acceptance and competitive pricing.